This document discusses the Docker ecosystem and provides an overview of containerization technologies. It covers the history of containerization from mainframes in the 1960s to Docker in 2013. It discusses Docker's success due to cloud adoption, portability, and hybrid environments. It outlines the Docker ecosystem including Docker Engine, Docker Hub, Docker Machine, Docker Compose, Docker Swarm, and Kitematic. It also discusses companies in the Docker ecosystem like Docker Inc., CoreOS, Deis, Kubernetes, Cloud Foundry/IBM Bluemix, and others.